DE1673408A1 - DEVICE FOR SPEED MEASUREMENT - Google Patents

Description

DR. MÖLLER-BORG DIPL.-ING. GRALFS DR. MANITZ

PATENT LAWYERS

Braunschweig, I? July 1967 Our reference: JTi / Kh - M

THE MAHGONI COMPANY LIMITED English Electric House, Strand London, W.0.2, England

Device for speed measurement

Priority: Great Britain 19 July 1966

No. 32308/66

Jl

The invention relates to a further development of the one described in German patent application M 69 883 IXb / 42o Device for speed measurement and is in particular for speed measurement in industrial / experienced, for example to measure the speed of application of a steel strip from a rolling mill. However, it is not applicable to such applications limited, but generally at speed. mossungon applicable, which also allows the measurement of vehicle evenness lock in.

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BATH OFUGINAL

After the main registration contains a facility for Measuring the speed of a moving one. Element compared to a reference point one or more photoelectric Converter devices, means to activate this device or devices by light from a constantly changing surface or constantly changing surfaces of the element, which are fixed with respect to the reference point, as well as means for the movement of said element with respect to the reference point of the modulation of the light which strikes the device or devices, depending on the speed of movement to take advantage of.

According to one embodiment of the in the main application described device, a light projector is arranged so that it is a light and on the element Projected shadow patterns that have lines that run transverse to the direction of relative movement of the element, wherein the light reflected from the area of the pattern is projected onto a photocell. The electric Output from this cell contains a major component a frequency that depends on the relative movement of the element and on the distance in the direction of movement transverse lines is. By measuring this Fx 'sequence in any known manner, the relative speed to be determined.

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BATH ORIGINAL

According to the invention, a device for measuring speed created according to the principles of the facility described in the parent application works, but has a simpler structure. In particular, according to the invention, a device for measuring speed is intended be created at an electrical output that is one of the speed dependent main frequency component is obtained without a line pattern of light and shadow is optically projected onto the surface whose speed is to be measured. By avoiding the optical projection of such a line pattern can significantly simplify the required optical equipment and be cheaper.

According to the invention, a device for measuring speed of a moving element with respect to a reference point at least one photoelectric Transducer device and means to this device activation by light from a constantly changing surface, which is fixed with respect to the reference point, with this facility is so constructed and arranged as to give the light from the surface a number of in equal mutual Light-sensitive lines arranged at a distance, these lines being at an angle (preferably a right angle) to the direction of movement of the

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Extending light with respect to the facility. The "moving element" can be an element of material (for example a moving steel belt), or it can just be a picture, a pattern or a representation of light and shadow moving across a solid surface exist.

According to one embodiment of the invention, the photoelectric converter device consists of one Selenium cell or similar arrangement with a number of mutually parallel and equally spaced arranged wire or strip electrodes with selenium (or a other suitable material, with photosensitive resistance such as doped germanium), with alternating successive electrodes with one clamp of the cell and the "remaining electrodes" with the other Terminal of the cell are connected.

According to a further embodiment of the invention, there is the photoelectric converter device from a selenium cell or a similar cell with a selenium layer (or another suitable Material with photosensitive resistance), with two comb-like shaped electrodes on this layer are provided, each with a different

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Terminal of the cell is connected. The "teeth" of the combs are arranged parallel to one another and at the same distance from one another, with the teeth of the two electrodes are pushed into each other and have a mutual distance.

According to a third embodiment of the invention there is the photoelectric converter device from a selenium cell or another cell with a attached to a metal inertia electrode Selenium layer (or other suitable material

on with photosensitive resistor), whereby / that of the Electrode remote side of the layer a second electrode with a plurality of parallel, same mutually spaced lines or stripes connected to one another is provided.

It can be seen that the principal frequency component required, which depends on the speed, in the electrical output of the photoelectric Converter device by the movement effect of the light over the same distance having photosensitive Lines is obtained which are presented to the relatively moving light by the device. It is known, of course, a selenium cell made of parallel wire or strip electrodes with

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see selenium build up. In these "known cells however, care is not taken to ensure equality of mutual. Distance between the wire or strip electrodes is guaranteed, as must be the case with the invention, if one is sufficiently good defined high frequency component that depends on the speed depends, should be obtained. In addition, these known cells are the number of electrodes per unit length (i.e. the dimension at right angles to the direction of extension of the Wire or strip electrodes) considerably below the value usually found in a cell for execution of the invention is required. As a practical value, one according to the invention can be used Cell assume that the electrodes are each about 0.254- Eua (0.01 ") wide and by the same amount are distant from each other. This shows that the electrode system used in the device according to the invention a line is more related to an optical grating than is the case for the electrode arrangement known cell applies.

Preferably, the electrodes of a cell used in practicing the invention are made up of rods (e.g. made of aluminum or gold), which in a vacuum on the selenium or another photosensitive resist

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stand material are applied.

Further details and advantages are given below explained with reference to the drawing. In this shows:

Fig. 1 is a schematically illustrated, perspective view of an embodiment of the invention, and the

Fig. 2, 5 and 4- partially broken perspective shown Views of three forms of selenium cells usable as cell 0 of FIG.

Figures 2, 3 and 4 give the individual cells only schematically again, with no attempt being made to obtain the To show electrodes or their mutual distance true to scale.

Fig. 1 shows the application of the invention for measuring the speed of a rolling mill (not shown) exiting steel strip S. A light source L illuminates an area A on the strip, where the area is shown as a large, circular spot, but also any other suitable shape and size can have. When the tape is hot enough

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BATH ORIGINAL

to get enough light or radiation to activate itself of the light-electrical converter used, the source L can be dispensed with. The light coming from the tape is projected onto a selenium cell C, which is designed in such a way that its electrical output is a main frequency component which depends on the speed of movement of the belt. The light is directed to cell C by means of a suitable lens arrangement O focused. The output of the cell O is by means of an amplifier M amplified, and the measurement of the speed of movement is carried out by means of a frequency meter F, the Freqzenz of the main component and can be directly calibrated in units of speed.

One embodiment of cell C is shown in FIG. This cell consists of a carrier plate 1, for example made of fiberglass, "on the mutually parallel, equally spaced wires or metal strip electrodes 2 deposited thereon are preferably provided, between which selenium 3 is located. The selenium is suitably formed as a layer on the plate, with the electrodes on this layer are upset. Alternating one after the other Electrodes are connected to a terminal 4- of the cell, and the remaining eggs are on the other Terminal 5 · The cell is positioned so that the electrodes are perpendicular to the direction of movement of the

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BAD ORfGiNAL

Band 1 (Fig.l), as "seen" from the cell, extend.

In the embodiment shown in FIG

the electrodes are formed by the "teeth" of two nested metal "combs" 12 and 22 which on a layer 3 of selenium on a glass fiber carrier plate 1 are applied. One comb is connected to terminal 4 and the other to terminal 5.

In the embodiment shown in FIG. 4, only a single metal comb 32 is made of a layer 3 Selenium applied, which is applied to a metal carrier plate 6 (e.g. brass). The comb is with connected to a terminal 5, and the carrier plate rests on the other terminal 4 ·.

The selenium cell can be replaced by another cell that has another suitable cell instead of selenium Material such as doped germanium with photosensitive resistance is used.

In all cases, the electrodes are preferably applied in a vacuum and can, for example, from deposited aluminum or gold. For

en. "

In the following, some practical values should be illustrated

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for the embodiment of Figure 3 which is presently preferred. The base plate 1 can consist of a square with side lengths between 12.7 and. 25.4 mm (1/2 "to 1 ^{! 1} square), the selenium layer can be 0.381 mm (0.015") thick, and the thickness of the metal combs can be between 0.0254 and 0.0508 mm (Ο, ΟΟΓ 'to 0.002 "), with each comb tooth being 0.254 mm (0.010") wide and the spacing between adjacent intermeshing teeth (one from each comb) also being 0.254 mm (0.010 ").

In the embodiment shown in FIG. 1, this is moving element - the steel belt S - whose speed is to be measured, a material element, that moves with respect to cell C itself. However, it is not necessary that this always be the case since the "moving element" is also just an image φ or sin H-rster or an image of light and shadow that moves on a solid surface. For example, the "moving element" could a light and shadow image or one on the screen of a cathode ray tube, e.g. on a P.P.I. radar display device, generated representation. Obviously, the device of Figure 1 would increase the speed of movement measure such an image in a special direction across the screen of the sight tube, although itself the screen of the pipes itself does not move.

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Claims (1)

Claims 1. Device for measuring the speed of a moving element with at least one photoelectric converter device in relation to a reference point, Means to this device or these devices of activation by light from one Constantly changing area or constantly changing areas of the element that are opposite to the reference point are fixed, suspend, as well as with arrangements to the movement of the element relative to the Reference point for modulating the light that strikes the device or devices, depending on the speed of the movement, according to patent .... (patent application M 69 883 IXb / 42o), characterized in that the device is designed and arranged in such a way that that the light coming from the surface has a number of equal mutual distances photosensitive lines are presented and that these lines are at an angle to the direction of movement of the light extend relative to the device. 2. Device according to claim 1, characterized in that that the angle is a right angle. 209885/0317 BATH ORIGINAL 3. Device according to claim 1 or 2, characterized in that that the moving element is an actual element of material. 4. Device according to claim 1 or 2, characterized in that the moving element is a itself is an image, pattern, or a light and shadow display that moves over a solid surface. 5. Device according to one of claims 1 to 4, since " characterized in that the photoelectric converter device is a selenium cell or a is similar cell, which is a number of mutually parallel, equally spaced apart Wire or strip electrodes with in the spaces arranged selenium or another photo-sensitive Material consists, and that alternating successive electrodes with a clamp of the cell and the remaining electrodes are connected to the other terminal of the cell. 6. Device according to one of claims 1 to 4, characterized in that the photoelectric Converter device consists of a selenium cell or a similar cell with a selenium layer, on which two comb-shaped electrodes are applied, each with a different terminal of the 209885/0317
BATH ORIGINAL Cell is connected , and that the teeth of the combs are parallel to each other and have the same mutual distance, the teeth of the electrodes are pushed into each other and have a mutual distance. · Device according to one of claims 1 to 4-, characterized in that the photoelectric converter device consists of a selenium cell or a similar cell with a selenium layer or similar layer applied to a wetall carrier electrode and that on the layer removed from this electrode side of the layer a second electrode is provided which has a plurality of parallel, equal mutual distance having lines or strips which are connected together. 8. Device according to one of claims 5 to 7 »characterized in that the electrodes of the Cell consist of metal lamellas, which are placed in a vacuum on the selenium or other photosensitive resistance material were deposited. 209885/0317 ORIGINAL BATHROOM. Blank page